Meat-curing salt composition



United States Patent MEAT-CURING SALT COMPOSITION Lloyd A. Hall andCarroll L. Griffith, Chicago, 11]., as-

signors to The Griffith Laboratories, Inc, Chicago, Ill., a corporationof Illinois N0 Drawing. Application July 1, 1955, Serial No. 519,614

14 Claims. (Cl. 99-222) The present invention relates to curing saltcompositions, and more particularly to the production of an improvedcomposition of sodium chloride crystals housing alkali metal salt ofeither one or both of nitric acid and nitrous acid, and especially to anon-caking composition.

The flash-drying of a solution of sodium chloride containing alkalimetal nitrite or alkali metal nitrate, or both, to form sodium chloridecrystals housing said other salt as heart-like centers, is fullydescribed in U. S. patcuts to Gritfith No. 2,054,624 and No. 2,054,626,and to Hall No. 2,145,417, No. 2,668,770 and No. 2,668,771.

The basic composition is first described in the said Grifiith patentswherein it is disclosed that such crystals may be formed byflash-drying, as on heated rolls, a strong solution of sodium chloridecontaining a minor proportion of the nitrogen-containing meat-curingsalts. The resulting crystals have the characteristic cubic form ofsodium chloride crystals, but under the microscope there may be seenwithin them heart-like centers which are the nitrogen-containing curingsalt. It is also disclosed that the rapid crystallization produces anunstable mass of crystals including a very small quantity of water whichis gradually decreased or increased according to equilibrium contentwith the environment. As formed, the environment is very humid so thatthe initial change is release of moisture. This takes place in the drumsin which the material is stored, and as a result, the mass tends to cakeon standing after the initial packaging.

The process and the character of the crystals are more scientificallyexpounded in the publication of Clark and Hall, Industrial andEngineering Chemistry, vol. 33, p. 98 (1941). As shown in saidpublication, all of the curing salt is included when the amount issmall, and the included amount varies somewhat with the proportions inwhich the nitrite salt and nitrate salt are present. The followingillustrates:

Table 1 Percent Percent Percent Percent NaN 02 N aNO; NaOl InclusionSince these crystals are manufactured and variously stored before use inthe meat-packing industry, it has been a commercial disadvantage thatthe product gradually cakes in the shipping container. Numerousexpedients have been tried to prevent the caking, but only to a degreehas it been minimized, as evidenced by proice longing the time untilcaking occurs. One of the earliest methods of minimizing the caking isdescribed in the Grifiith patents wherein a hygroscopic agent is added,such as corn sugar or glycerine, which is believed to take up the wateras it is released from the crystals, and preferentially to take it upfrom the atmosphere, and thus provide an aqueous partition betwen thecrystals.

It has been established that the caking is due in part at least to theinitial liberation of water from the crystals, and not wholly from theabsorption of moisture from the atmosphere, which commonly is the causeof caking in many salt compositions.

The above-cited patents all disclose the problem of caking and variousways to minimize it. Hall No. 2,145,417, for example, teaches that whencommercial corn sugar is used, with or without glycen'ne, as ahygroscopic agent, the caking is minimized, but that the nitrite valueis lowered on aging. Because of a trace of acidity in commercial cornsugar, Hall stabilized the composition with respect to nitrite by addinga buffering agent to insure a pH value not below 7.4. Sodium carbonate,sodium bicarbonate and disodium phosphate in very small amounts arenamed as suitable bufien'ng agents. A pH of the solution above 7.4 andupwardly to values as high as 10.3 does not afiect the quality of thesolution to form jacketed crystals, nor does it operate to preventcaking.

The Hall Patents No. 2,668,770 and No. 2,668,771 also refer to thecaking problem and disclose the use of hygroscopic agents to minimizeit. The patents name specifically corn sugar, glycerine, sorbitol andpropylene glycol. No. 2,668,770 describes the removal of hardness fromthe water employed in the process, by use of the ion-exchangeprocedures. Elimination of the hardness in no way minimizes the caking,and the product so produced still required the use of hygroscopic agentto minimize caking. Hall Patent No. 2,668,771 is based upon thediscovery that traces of certain metallic cations function as oxidationcatalysts leading to slow conversion of nitrite salt to nitrate salt,and to remedy this defect, the solution, normally containing suchcations, is treated with a small but sequestering amount ofpolyphosphate salt, such as sodium tripolyphosphate, to capture suchmetal cations and render them ineiiective as catalysts. This specialtreatment of the water in no way reduces the tendency to cake, noreliminates the necessityto use hygroscopic agent.

Although various hygroscopic agents minimize rather than prevent thecaking of the above-described compositions, it has not been found thatthe quantity of such agent may be increased within practical ranges toprevent caking. The present invention is based upon the discovery thatthe compositions containing the hygroscopic agent may be greatlyimproved and the caking may be further delayed and even prevented by theinclusion of a small quantity of a certain salt material present in thesolution to be flash-dried.

It is, therefore, an object of the invention to make an improved curingsalt composition of the type having sodium chloride crystals housingnitrogen-containing curing salt.

It is a particular object to minimize and even prevent the caking ofsuch curing salt composition.

It is also an object to improve the physical character of thecomposition as originally formed and to retain that character in storageagainst change by eaking.

In the various processes described in the above-cited patents, theflash-drying of the solution on heated rolls having a temperature in therange from 310 F. to 330 F., and preferably at 320 to 325 F, dischargesa mass of powder-like crystals which are initially free flowing. It is acommercial necessity to package the material in drums for storage,shipment and then more storage. it has now been discovered that whenalkaline alkali metal orthophosphate is present in a small amount in thesolution to be flash-dried, the crystals are initially more powdery incharacter, and flow like water, with a greatly lessened or lost tendencyto cake generally proportional to the amount of orthophosphate saltpresent. The resulting non-caking compositions retain the ability toflow like water.

Whether or not a composition cakes is a matter relative to time and alsostorage conditions. Initially, the composition is a mass of free-fiowingcrystals. The prior art compositions, even though minimized in thetendency to cake by inclusion of a hydroscopic agent, have caked asearly as two weeks. A suitable commercial composition should benon-caking during the period from manufacture to consumption of thecontents of a container in which it is shipped.

The compositions may be varied for different conditions. For example,when the drums are to be stored in aware/house, the composition shouldremain free-flowing during the storage period. When drums are not storedin a warehouse, the composition is usually consumed in from 30 to 60days after manufacture, and as a safety factor should be free-flowingfor at least 90 days. Also, there are consumers located close to theplace of manufacture who use the product within a much shorter timefollowing manufacture.

The alkaline alkali metal orthophosphates are either potassium orsodium, and, in the case of the sodium salts, the ingredients referredto herein are trisodium phosphate monohydrate and disodium phosphatedihydrate. These have, respectively, molecular weights of 182 and 178.In consequence, the specification of amounts of percentages by onefigure applies to both types of salt calculated as said crystal-formingredients. No difference in result appears when using the potassiumsalts over using the sodium salts, and this is believed to be due to thepredominance of sodium ions in the solution to be flash-dried. Thisseems to predetermine a predominance of the sodium orthophosphate saltsin the final product.

In accordance with the present invention, the amount of alkaline alkalimetal orthophosphate included in the composition is varied in accordancewith the expected conditions of storage before consumption. In general,it has been found that the inclusion of said sodium salt ingredients inamount upwardly from 2% adds greatly to the non-caking life of thecomposition otherwise containing hygroscopic agent. Amounts of saidsodium salt ingredient up to of the salt composition have been used withgood results, but not over 3% is required for present-day commercialpractices. For the average user,

amounts in the range from 2% to 5% are suitable and are preferred, butit is to be understood that the invention contemplates using any amountabove 2% which adds to the non-caking lifeof a composition otherwisewithout it. When the anti-caking agents in a composition consist of ahygroscopic agent and alkaline alkali metal orthophosphate, theinvention contemplates that the latter be present in amount at leastequivalent to 2% calculated as said sodium salt ingredients. In theabsence of the hygroscopic agent, the same amounts of the alkalinealkali metal orth'ophosphate are not effective, leading to theconclusion that the hygroscopic agent and the salt are synergistic.

In a co-iiled application Serial No. 519,616 of Hall and Kalchbrenner,it is shown that alkali metal citrate is an effective anti-caking agentin combination with the hygroscopic agent. In another co-filedapplication Serial No 19,615 of Hall and Kalchbrenner, sodium citrate isused in combination with alkaline alkali metal orthophosphate. Inparticular therein, citric acid and trisodium ortliophosphatemonohyd-rate may be the initial ingredients, so used that they react toform sodium citrate 4, and disodium orthophosphate, with or without anyexcess of the trisodium phosphate.

The present invention as practiced with trisodium phosphate alone givesbetter results than with an equal amount of disodium phosphate usedalone. However, when the solid curing salt composition is dissolved intap water to make a pickling brine, there is cloudiness from theformation of insoluble phosphates from the mineral hardness in thewater. The cloudiness is more prominent in the case of trisodiumphosphate. Consumers are accustomed to clear brine, so when it isdesired to overcome the cloudiness a small amount, such as 1% of thewhole, of sodium tripolyphosphate is included to sequester the mineralhardness. Sodium tripolyphosphate per so does not function like theorthophosphate salts of the present invention. Sodium tripolyphosphateto avoid cloudiness may be replaced by sodium citrate, which adds to theanti-caking 7 function as set forth in said co-filed application SerialNo. 519,615. Accordingly, the present invention is directed to the useof alkaline alkali metal orthophosphates as anti-caking agents with orwithout sequestering agents such as sodium tripolyphosphate and sodiumcit-rate.

In carrying out the invention, the various compositions known andcommercially made need not be changed except by the addition of thesalts as stated above in substitution for part of the sodium chloride.The selected salt may be either dissolved as an ingredient in thesolution which is to be flash-dried, or it may be formed from suitablereactants in the final solution or in the course of forming the finalsolution. In forming the final solution, any one or more of the variousalkaline agents used in making the solution should be present inquantity to give a desirable pH of at least 7.4 to assure retention ofnitrate value.

The invention is illustrated by variations in two basic compositions ofwhich the salt ingredients and the proportions thereof to each other areWell established in commercial use. These are shown in Table II.

Table II 1 The amount given is decreased by the amount of material addedin the examples below.

In the following examples, a heated solution containing the various saltincredients is run onto slowly revolving drums heated to a temperaturein the range from 310 F. to 330 F. Powdery crystals are scraped from therolls and conveyed by worm-screw through a cooling tunnel and packedinto drums holding about 300 pounds, with the crystals at or below roomtemperature.

No absolute measure of the desired effect has been found, and only ageneral estimate from numerous batches has been made. Temperature andhumidity differences at the time of manufacture, and also during thestorage period, are influential, and in the absence of controlledsurroundings, exact values are difficult to secure.

The following Table Illl gives the data as follows:

Column 1: Example number.

Column 2: Formula of Table II.

Column 3: Quantity of orthophosphate salt.

Column 4: Quantity of agent for sequestering.

Column 5: Percent content of tri-or di- ,(see footnote of table).

Column 6: Percent content of agent for sequestering.

Column 7; Comment on non-caking life.

Table III Example Formula Oz. of Oz. 01- Percent Percent Comment 1 2226Tri- 1 5 6 months. 1 2226 Tri- 432 STP 1 7 months. 1 2226 Tri- 660 NaOitL... 5 1 o. 1 2226 Tri- 432 Cit 5 1 D0. 1 1336 Tn- 3 0 5 months 1 1336Trl- 3 1 D0. 1 1336 TIP 3 1 D0. 1 1336 Tn- 3 1 Do. 1 890 Tri 2 0 4months. 1 890 Tri- 432 ST? 2 1 Do. 1 890 Tri- 660 NaCit. 2 1 D0. 1 2226Di- 5 0 5 months. 1 1336 D 3 0 4 months. 1 1336 D1- 3 1 D0. 1 1336 D 3 1D0. 1 890 Di-. 1 2 0 3 months. 1 890 Di- .1 2 l 4 months. 1 890 Di- 2 1Do. 1 1 1 2 weeks. 2 1 Do.

I Di-= NagHP 04.21120 3 STP=Anhydrous sodium tripolyphosphate 4NaCit=Sodium citrate dihydrate (m. w.=294) 5 Cit=Anhydrous citric acid(In. W.=l92) When the examples of Tables III are repeated using FormulaN0. 2 of Table II, anti-caking life is the same as indicated in TableIII.

In the foregoing examples, the glycerine as the hygroscopic agent may bereplaced in whole or in part by an equal weight of either corn sugar, orpropylene glycol or sorbitol, or a mixture of such agents, withsubstantially the same results as described. The hygroscopic agent hasanti-caking properties only to a degree such that increasing its contentdoes not add to the eifect. The presence of a small amount of alkalinealkali metal orthophosphate adds greatly to the effect of thehydgroscopic agent, but in the absence of the latter, it has littleeifect to minimize caking. Accordingly, the combination of the alkalinealkali metal orthophosphate and of hygroscopic agent is a synergisticone.

From the foregoing description and explanation, it will be apparent thatthe invention may be practiced with numerous variations not limited tothe precise illustrations herein given, and such changes andmodifications are contemplated as falling within the scope of theinvention as expressed in the appended claims.

We claim:

1. A curing salt composition consisting of the flashdried crystals of anaqueous solution having a pH not under 7.4 and having solute consistingessentially of a major portion of sodium chloride, a minor portion ofcuring salt selected from the group consisting of alkali metal nitrite,alkali metal nitrate, and mixtures thereof, and a small quantity ofanti-caking material comprising a hygroscopic agent and alkaline alkalimetal orthophosphate in amount in at least 2% of the composition,calculated as NaaPOaHzO.

2. The product of claim 1 wherein the alkaline orthophosphate salt ispresent in amount in the range from 2% to 5% of the composition,calculated as Na3PO4.H2O.

3. The product of claim 1 in which all the salts are sodium salts.

4. The product of claim 1 in which there is present a small percentageof agent which sequesters mineral phosphates resulting from the mineralhardness of water in a meat-pickling brine containing the salt.

5. The product of claim 4 in which the sequestering agent is sodiumtripolyphosphate.

6. The product of claim 1 in which the hygroscopic agent is glycerine.

7. The product of claim 2 in which the hygroscopic agent is glycerine.

8. The product of claim 3 in which the hygroscopic agent is glycerine.

9. The product of claim 4 in which the hygroscopic agent is glycerine.

10. The method which comprises forming a solution at a pH not under 7.4consisting essentially of alkaline alkali metal orthophosphate, sodiumchloride, hygroscopic material, and curing salt selected from the groupconsisting of alkali metal nitrite, alkali metal nitrate, and mixturesthereof, the curing salt being present in sufiiciently small amount sothat a major portion thereof will be jacketed by the sodium chloride inthe hereinaftermentioned flash-drying, and the said orthophosphate saltcalculated as NasPOaHzO being present in amount upwandly from about 2%of the solid content of said solution, and flash-drying the saidsolution.

11. The method of claim 10 in which all the salts are sodium salts.

12. The method of claim 10 in which a small percentage of sodiumtripolyphosphate is present in quantity to sequester mineral hardness ofwater in a meat-pickling brine containing the salt composition,

13. The method which comprises forming a solution at a pH not under 7.4consisting essentially of alkaline alkali metal orthophosphate, sodiumchloride, glycerine, and curing salt selected from the group consistingof alkali metal nitrite, alkali metal nitrate, and mixtures thereof, thecuring salt being present in sufficiently small amount so that a majorportion thereof will be jacketed by the sodium chloride in thehereinafter-mentioned flash-drying, and the said orthophosphate saltcalculated as Na3PO4.H2O being present in amount upwardly from 2% of thesolid content of said solution, and flash-drying the said solution.

14. The method which comprises forming a solution at a pH not under 7.4consisting essentially of alkaline alkali metal orthophosphate, sodiumchloride, glycerine, and curing salt consisting of sodium nitrite andsodium nitrate, the curing salt being present in sufiiciently smallamount so that a major portion thereof will be jacketed by the sodiumchloride in the hereinafter-mentioned flash-drying, and the saidorthophosphate salt calculated as NasPO4.H2O being present in amountupwardly from 2% of the solid content of said solution, and flash-dryingthe said solution.

References Cited in the file of this patent UNITED STATES PATENTS2,145,417 Hall Jan. 31, 1939 2,596,067 Brissey May 6, 1952 2,668,771Hall Feb. 9, 1954

1. A CURING SALT CONSISTING OF THE FLASHDRIED CRYSTALS OF AN AQUEOUSSOLUTION HAVING A PH NOT UNDER 7.4 AND HAVING SOLUTE CONSISTINGESSENTIALLY OF A MAJOR PORTION OF SODIUM CHLORIDE, A MINOR PORTION OFCURING SALT SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL NITRITE,ALKALI METAL NITRATE, AND MIXTURES THEREOF, AND A SMALL QUANTITY OFANTI-CAKING MATERIAL COMPRISING A HYGROSCOPIC AGENT AND ALKALINE ALKALIMETAL ORTHOPHOSPATE IN AMOUNT IN AT LEAST 2% OF THE COMPOSITION,CALCULATED AS NA3PO4.H2O.